Hello Ola,
I understand you are unable to create a ringtone with songs you purchased. I can understand how upsetting this can be. My name is Alexis and I will be happy to look into this for you today.
I have taken a look into this for you and the reason you have been unable to create a ringtone is because ringtones are not currently offered in the Sweden iTunes Store.
Apple recognizes that no one is better qualified to provide feedback about iTunes than the people who use it.
I encourage you to use the iTunes Feedback page to submit your comments to have ringtones added to the Sweden iTunes Store:
Apple - iTunes - Feedback
Your efforts to share your feedback are very much appreciated. Ola, thank you for contacting the iTunes Store customer support team. Have a wonderful day.
Sincerely,
Alexis
iTunes Store Customer Support